Information handling system thermal control by energy conservation

ABSTRACT

A thermal state within an information handling system enclosure is managed within predetermined constraints by estimating thermal energy introduced to the enclosure by power dissipation to electronic components and thermal energy removed from the enclosure by a cooling airflow generated by a fan. A desired bulk temperature of a cooling airflow is attained at a predetermined position in an enclosure by selecting a fan speed and power allocation to the components that conserves energy within the enclosure at a predetermined thermal state.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to the field of informationhandling system thermal control, and more particularly to informationhandling system thermal control by energy conservation.

2. Description of the Related Art

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Information handling systems are typically built by assembling a varietyof components into a chassis so that the components cooperate to processinformation. For example, a blade server information handling system hasa chassis that accepts plural blade server modules by sharing power andnetworking resources of the chassis with the blade servers under thecontrol of a chassis management controller (CMC). Each blade servermodule typically has a motherboard with one or more central processingunits (CPUs), power distribution circuits, persistent storage deviceslike hard disk drives or solid state drives, memory like DRAM,networking components, mezzanine cards and a baseboard managementcontroller (BMC) that provides management functions like remote power-upand power-down. The chassis management controller manages powerresources by distributing power allocations to the blade modules. Abaseboard management controller on each blade module powers componentswithin the blade module to operate within the power allocation budgetprovided by the chassis management controller. The chassis managementcontroller also typically manages cooling resources provided by a fancontroller and one or more cooling fans based upon thermal informationprovided from the baseboard management controllers, such as thermalmeasurements at components within each blade module. In serverinformation handling systems, a bulk air temperature represented by thetemperature of a cooling airflow exhaust is sometimes managed byadjusting fan speed to maintain less than a maximum exhaust temperature.

One difficulty with management of thermal conditions in an informationhandling system chassis is that thermal conditions tend to varythroughout a chassis enclosure. Variance in thermal conditions can besignificant in a modular information handling system, such as a bladeinformation handling system, where a particular module has a higherworkload than other modules in the same chassis. Variance in thermalconditions can also be significant across an information handling systemmodule where different components of the module operate at varyingworkloads. For example, thermal conditions near a central processingunit typically increase during the performance of processing-intensiveoperations. In order to monitor thermal conditions at processors,processors typically incorporate a thermal sensor, such as a thermistor,and logic to report thermal conditions measured by the thermal sensor toa system thermal manager, such as firmware instructions running on aBIOS, BMC, CMC, and/or fan controller that manages cooling fan operatingspeeds. Processors are typically physically located “upstream” of acooling airflow provided by a cooling fan to provide efficient coolingsince processors generally are one of the greatest sources of thermalenergy in a chassis and also usually among the most heat sensitive ofcomponents. Other components are typically disposed in the chassis“downstream” of the processor so that cooling airflow passes by theprocessor first and then passes by less-heat sensitive components.

One difficulty with managing thermal conditions in an informationhandling system chassis enclosure is that not all components integratethermal self-protection capabilities in order to maintain reliabilityconformance during thermal excursions, such as when a cooling systemfails, extreme ambient environmental temperatures exist or ultra-highstress operating conditions exist that exceed the capabilities of achassis' cooling system. For example, a processor operating in extremethermal conditions will throttle its power consumption to reduce heatgeneration and maintain its internal temperature within a desiredconstraint; however, mezzanine cards, some hard disk drives and many onboard devices like networking, chipset, power distribution and BMCdevices, do not include thermal sensors or thermal self-protectioncapabilities. Since these thermally “helpless” components are oftendownstream of a cooling airflow, the three primary ways of ensuringadequate cooling of “helpless” components are to throttle the helplesscomponents, to increase fan speeds so that a greater cooling airflowexists to remove excess thermal energy or to throttle upstreamcomponents so that less thermal energy is generated to reduce thedownstream cooling airflow temperature. Unfortunately, if components donot have thermal sensors then no direct measurement of thermalconditions at the components exists to provide direct control overthermal conditions at the component.

In order to manage thermal conditions within an information handlingsystem chassis for components that do not include thermal sensors, someinformation handling systems dispose thermal sensors near componentsthat monitor localized air temperatures. Unfortunately, as air flowsthrough an information handling system enclosure, air streamlines acrossthe enclosure can have significant variation in temperature even acrosssmall linear separations. In chassis enclosures that include pluralmodules, such as a blade chassis, an exhaust temperature of a coolingsubsystem that cools plural modules does not necessarily indicatethermal conditions at any one module because different modules often rundifferent loads. For example, a module running at a high load can haveextreme thermal conditions even though the bulk temperature of a coolingsubsystem exhaust is in a normal range. One solution for thermalmanagement of components that lack thermal sensors is to nest a largearray of onboard thermistors to average thermal readings for a moreaccurate “bulk” air temperature. This solution tends to increase systemcost by the addition of plural interfaced sensors and system complexityby having multiple thermal measurements and multiple failure points.

SUMMARY OF THE INVENTION

Therefore a need has arisen for a system and method which measuresinformation handling system thermal conditions to manage cooling systemoperation and component throttling for managing thermal conditions ofcomponents that lack thermal monitoring.

In accordance with the present invention, a system and method areprovided which substantially reduce the disadvantages and problemsassociated with previous methods and systems for managing cooling systemoperation and component throttling to manage thermal conditions ofcomponents that lack thermal monitoring. A thermal state at apredetermined location within a chassis enclosure is managed by applyingpower dissipation of electronic components and inlet temperature of acooling airflow to set a fan speed that establishes a desired coolingairflow rate.

More specifically, an information handling system has plural componentsdisposed in an enclosure that cooperate to process information. Acooling fan provides a cooling airflow from an inlet, past thecomponents and out an outlet. The components are powered by a powersupply under the direction of a power manager, which monitors powerdissipated by the components. A thermal manager interfaced with thepower manager and the cooling fan establishes a cooling fan speed tomaintain a predetermined thermal state within the enclosure by applyingpower dissipation of a set of components and a temperature sensed at thecooling fan inlet. For example, in a modular information handling systemhaving plural processing modules, such as a blade server having pluralblades, the thermal manager manages the thermal state associated with aprocessing module by applying the power dissipated by the components ofthe processing module and the inlet temperature for cooling airflow todetermine a cooling fan speed that will provide a sufficient coolingairflow to maintain less than a predetermined bulk temperature with theprocessing module. If the cooling fan cannot provide an adequate coolingairflow, then the thermal manager reduces power consumption of one ormore components to maintain the desired thermal state in the processingmodule. For instance, the thermal module throttles a processor eventhough the temperature sensed at the processor is in a normal operatingrange so that downstream components will have adequate cooling, eventhough the downstream components do not have direct temperature sensing.The adequate cooling of the downstream components is ensured by cooledairflow.

The present invention provides a number of important technicaladvantages. One example of an important technical advantage is thatthermal conditions within an information handling system enclosure areaccurately measured without having to dispose an array of sensorsthroughout the enclosure. Measurements of enclosure thermal conditionsestimated by the Law of Conservation of Energy are applied to providethermal control for downstream components that lack thermal sensors. Ifthermal conditions within the enclosure exceed a threshold associatedwith operation of unmonitored components, the thermal conditions aremanaged to maintain an operating environment acceptable to theunmonitored components. For example, upstream components are throttledto reduce thermal energy released to a cooling airflow, fan speed isincreased to reduce cooling airflow temperature or unmonitoredcomponents are throttled or powered down to reduce downstream thermalenergy release or prevent damage to the unmonitored components. Bulkenclosure thermal energy estimates derived from the Law of Conservationof Energy combined with thermal measurements from monitored componentsoffers a more precise overall picture of thermal operating conditions atan information handling system without unnecessary thermal sensors andsystem complexity.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features and advantages made apparent to those skilled in theart by referencing the accompanying drawings. The use of the samereference number throughout the several figures designates a like orsimilar element.

FIG. 1 depicts a side view of an example of an information handlingsystem that manages a thermal state in an enclosure by adjusting fanspeed based on power dissipation and cooling airflow inlet temperature;

FIG. 2 depicts a functional block diagram of a process for managing aninformation handling system enclosure thermal state by adjusting fanspeed based on power; and

FIG. 3 depicts a flow diagram of a process for managing an informationhandling system enclosure thermal state by adjusting fan speed and powerdissipation.

DETAILED DESCRIPTION

A thermal state within an information handling system enclosure ismanaged by adjusting fan speed for a cooling airflow in the enclosurebased upon an inlet temperature of the cooling airflow and powerdissipated to components running within the enclosure. For purposes ofthis disclosure, an information handling system may include anyinstrumentality or aggregate of instrumentalities operable to compute,classify, process, transmit, receive, retrieve, originate, switch,store, display, manifest, detect, record, reproduce, handle, or utilizeany form of information, intelligence, or data for business, scientific,control, or other purposes. For example, an information handling systemmay be a personal computer, a network storage device, or any othersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include random accessmemory (RAM), one or more processing resources such as a centralprocessing unit (CPU) or hardware or software control logic, ROM, and/orother types of nonvolatile memory. Additional components of theinformation handling system may include one or more disk drives, one ormore network ports for communicating with external devices as well asvarious input and output (I/O) devices, such as a keyboard, a mouse, anda video display. The information handling system may also include one ormore buses operable to transmit communications between the varioushardware components.

Referring now to FIG. 1, a side view depicts an example embodiment of aninformation handling system 10 that manages a thermal state in anenclosure 12 by adjusting fan speed based on power dissipation andcooling airflow inlet temperature. In the example embodiment,information handling system 10 is a blade server having plural slots 14,each slot 14 accepting a blade information handling system module 16that processes information. For example, each blade information handlingsystem module 16 includes components that cooperate to processinformation, such as a CPU 18, RAM 20, a mezzanine card 22, a hard diskdrive 24, and a chipset 26 that communicate through a motherboard 28.The components are managed by a baseboard management controller (BMC)30, which selectively provides power to the components from a powersupply 32 by communicating with a power manager 34.

During operation of components disposed in enclosure 12, thermal energyis generated in varying amounts based upon the power consumption of thecomponents. For example, under a heavy processing load, CPU 18 usesincreased power and produces increased thermal energy as a byproduct ofprocessing information. Some components, such as CPU 18, include atemperature sensor that senses the temperature of the components duringoperations. Other components do not include a sensor that allows adirect indication of the component's temperature, such as some hard diskdrives and mezzanine cards as well as basic electronic componentsdisposed in motherboard 28, like resistors and capacitors. In varyingdegrees, the components have power consumption managed by logic runningin chipset 26 and/or on BMC 30. For example, BMC 30 manages powerconsumption of CPU 18 by selectively throttling the speed at which CPU18 executes instructions to reduce power consumption. As anotherexample, firmware in chipset 26 under the direction of BMC 30 removespower from mezzanine card 22 and hard disk drive 24 to reduce powerconsumption and the associated generation of thermal energy.

One or more cooling fans 36 disposed in enclosure 12 draws a coolingairflow through an inlet 38 and passes the cooling airflow over thecomponents and out an outlet 40 to remove excess thermal energy from thecomponents. In order to ensure proper operation of components withinenclosure 12, the thermal state within enclosure 12 is managed to staywithin defined constraints, such as a maximum bulk air temperature. Inthe example depicted by FIG. 1, CPU 18 is located upstream in thecooling airflow, meaning closer to inlet 38, since CPU 18 tends tocreate more excess thermal energy than other components and typicallyneeds a cooler temperature of the cooling airflow to obtain adequatecooling. Other components are located downstream of CPU 18, meaningcloser to outlet 40, since these components tend to produce less excessthermal energy. Downstream components obtain adequate cooling as long asthe increase in cooling airflow temperatures from upstream components isnot excessive; however, since some downstream components often do nothave direct temperature monitoring, such as by a temperature sensordisposed in the component, inadequate cooling airflow and/or excessivethermal energy production by upstream components can result in anovertemperature at downstream components.

In order to prevent an overtemperature of downstream components, athermal manager 42 manages the speed selected for cooling fan 36 bycommunicating a cooling fan speed to fan controller 44, which sets thespeed at which cooling fan 36 runs. Selection of an increased coolingfan speed results in a greater airflow, typically measured in cubic feetper minute (CFM), to provide increased thermal transfer of thermalenergy from components to the airflow and out outlet 40. Thermal manager42 selects a cooling fan speed that will maintain a predeterminedthermal state within enclosure 12, such as a bulk air temperature in theproximity of a selected set of components. The predetermined thermalstate is defined to provide operating conditions within the thermalconstraints of the components disposed within enclosure 12. For example,the predetermined thermal state is associated with a bulk airflowtemperature that is quantifiable by the temperature at outlet 40 or atemperature measured at various physical locations within enclosure 12,such as in a slot 14 or the space over a blade module.

Thermal manager 42 sets fan 36 speed to maintain a predetermined thermalstate within enclosure 12 by applying the Law of Conservation of Energyto enclosure 12. In summary, at a predetermined energy state, energyentered into the enclosure by dissipation of power at the componentsequals energy removed from the enclosure by absorption to the coolingairflow provided by fan 36. Heating of a fluid in motion is defined as:q=(mdot)(Cp)(dT)where q is the total energy dissipation, mdot is the mass flow rate ofthe energy absorbing fluid, Cp is the specific heat of the fluid, and dTrepresents the temperature rise of the fluid as a consequence of thermalenergy input. In a typical information handling system operatingcondition, the density and specific heat of the cooling fluid, typicallyair but sometimes liquid, are constant. Assuming constant density andspecific heat of air as a cooling fluid reduces the equation forconservation of energy in enclosure 12 toq=Q*K*dTwhere Q is the volumetric flow rate of the cooling fluid, such as airstated in cubic feet per minute (CFM), and K is a constant that combinesspecific heat and density of fluid for the units chosen for thesurrounding variables.

Thermal manager 42 maintains a predetermined thermal state in enclosure12 by apply an inlet temperature measured by an inlet temperature sensor46 and instantaneous power dissipation provided by power manager 44 to acharacteristic airflow equation defined for enclosure 12 to determine afan speed setting for fan 36. For example, a characteristic airflowequation soft or hard coded into thermal manager 42 yields a duty cyclefor fan 36:% Duty Cycle=A1(CFM Request)+B1where A1 and B1 are configuration constants describing the relationshipof a given chassis between airflow in CFM and fan duty cycle speedsettings. A characteristic airflow equation may be defined for anyparticular portion of an enclosure where a thermal state may be ofinterest, such as within a blade module or over a downstream portion ofa processing module that lacks direct monitoring of componenttemperatures.

If the cooling fan speed setting for a given CFM request is greater than100%, then the cooling fan cannot provide the necessary cooling airflowto maintain a predetermined thermal state in enclosure 12 for thecurrent power dissipation. If available cooling fan speed settings arenot sufficient to maintain the predetermined thermal state, then thermalmanager 42 commands a reduction in power consumption by one or more ofthe components disposed in enclosure 12. Thus, even though temperaturesmeasured at monitored components are within limits, such as atemperature measured at a CPU 18, thermal manager 42 can throttle CPU 18to reduce the thermal state within enclosure 12 and prevent overheatingof components downstream of CPU 18. Alternatively, thermal manger 42 canpower down downstream components that lack direct monitoring of theirthermal state to reduce power dissipation and thereby reduce the thermalstate within enclosure 12. In one embodiment, thermal manager 42 selectscomponents to have a reduced power consumption based upon an amount ofpower dissipation reduction that will provide a thermal state withinconstraints given available cooling fan speed settings. For example, ifa reduction of power dissipation by 10 Watts will provide thepredetermined thermal state with a fan duty cycle of 100%, then thermalmanager can select throttling of CPU 18 or power down of mezzanine card22 so that power dissipation is reduced by 10 Watts. In one embodiment,thermal manager 42 selects components to have a reduced powerdissipation based upon functions being performed by information handlingsystem 10. As an example, if current operations do not require a videocard disposed on a mezzanine card 22, then thermal manager 42 directsBMC 30 and/or chipset 26 to power down mezzanine card 22 so thatthrottling of CPU 18 is avoided.

In one embodiment, thermal manager 42 manages the thermal state atplural points in enclosure 12. For example, each of plural blade modules16 is allocated power by power manager 34 to ensure that the limits ofpower supply 32 are not exceeded. Power manager 34 monitors powerdissipation at each blade module 16 and reports the power dissipationfor each blade module 16 to thermal manager 42. Thermal manager 42applies the power dissipation at a blade module 16 to determine thethermal state of the blade module 16 so that each blade module 16 hasits thermal state individually monitored. Thermal manager 42 manages thethermal state within each blade module 16 by managing power dissipationof components of the blade module 16 based upon a characteristic airflowequation for the blade module. Thus, for example, even though enclosure12 overall has a thermal state within predetermined constraints, anindividual blade module 16 within enclosure 12 having a high workloadmay experience an overtemperature due to power dissipation of componentsat the blade module 16. Thermal manager 42 addresses local thermalstates within enclosure 12 based upon local power dissipation and localairflow characteristics to prevent local overtemperatures by throttlingor powering down selected components within the local thermal state orupstream of the local thermal state. In one alternative embodiment,thermal sensors may be disposed at various locations in enclosure 12,such as an exhaust sensor 48 or sensors within a blade module 16, for acomparison of measured bulk temperatures with expected bulktemperatures; however, an advantage of the present disclosure is thatmanagement of a thermal state within enclosure 12 is performed withoutrequiring temperature sensors that attempt to measure bulk airtemperature after heating by components.

Referring now to FIG. 2, a functional block diagram of a process formanaging an information handling system enclosure thermal state byadjusting fan speed based on power. At step 50, ambient air temperatureis sensed at the inlet for a cooling airflow. At step 52, powerdissipation by components of an information handling system is sensed.At step 54, ambient temperature and power dissipation are applied to amodel of the information handling system to determine a thermal state.The model can apply to a complete enclosure such as to estimate bulk airtemperature at an exhaust of the enclosure or to a portion of anenclosure, such as to estimate the bulk air temperature proximate aprocessing module, such as a server sled or blade. The thermal statethat results from step 54 is applied to a cooling fan state at step 56to determine a fan speed that will provide a cooling airflow for adesired thermal state of the bulk temperature modeled at step 54. Forexample, if all cooling fans are operational, values presented in table60 are applied for determining air flow from a fan duty cycle. If one ormore of plural fans have failed, values presented in table 62 areapplied for determining air flow from a fan duty cycle. In analternative embodiment, air flow rates are determined as part of acharacteristic airflow equation as described above. At step 66, the fanduty cycle is provided that will maintain a desired thermal state forthe enclosure or portion of the enclosure modeled at step 54. At step68, the fan controller sets the fan speed at the determined duty cycleto control the air flow so that a desired thermal state results.

Referring now to FIG. 3, a flow diagram depicts a process for managingan information handling system enclosure thermal state by adjusting fanspeed and power dissipation. The process begins at step 70 with a fanspeed setting output for maintaining a desired thermal state. At step72, a determination is made of whether the cooling fan can operate atthe fan speed needed to maintain the desired thermal state. If therequested fan speed is available, the process continues to step 74 toset the fan speed. If at step 72 the requested fan speed exceeds anavailable fan speed, the process continues to step 76 to reduce powerconsumption at one or more components so that the fan speeded needed tomaintain the desired thermal state does not exceed the available fanspeed.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions and alterations can bemade hereto without departing from the spirit and scope of the inventionas defined by the appended claims.

What is claimed is:
 1. An information handling system comprising: anenclosure having an inlet and an outlet; plural components disposed inthe enclosure and operable to cooperate to process information; acooling fan disposed in the enclosure and operable to generate a coolingairflow from the inlet to the outlet with a selected of plural availablefan speeds; a power supply operable to power the plural components; aninlet temperature sensor operable to sense airflow temperature at theinlet; and a thermal manager interfaced with the cooling fan, powersupply and inlet temperature sensor, the thermal manager operable toapply power dissipated by the power supply to one or more of thecomponents and the inlet airflow temperature to set a speed of thecooling fan that maintains a predetermined thermal state in theenclosure proximate the one or more of the components, the thermalmanager further operable to determine that the plural available fanspeeds will not maintain the predetermined thermal state and, inresponse, to select one or more components of the one or more componentsto power down to allow available fan speeds to maintain thepredetermined thermal state, the selected component having apredetermined thermal profile.
 2. The information handling system ofclaim 1 wherein the thermal manager is further operable to reduce powerconsumption by one or more of the plural components if the cooling fanset on full speed fails to establish the predetermined thermal state. 3.The information handling system of claim 2 wherein the thermal managerreduces power consumption by powering down one or more unmonitoredcomponents of the plural components, the one or more unmonitoredcomponents lacking a thermal sensor.
 4. The information handling systemof claim 3 wherein the one or more of unmonitored components comprises amezzanine card.
 5. The information handling system of claim 2 whereinthe thermal manager reduces power consumption by throttling a monitoredcomponent of the plural components, the monitored component having athermal sensor that provides a temperature associated with the monitoredcomponent to the thermal manager.
 6. The information handling system ofclaim 5 wherein the thermal manager is further operable to apply thetemperature associated with the monitored component to determine athrottled state for the monitored component that will maintain thepredetermined thermal state in the enclosure.
 7. The informationhandling system of claim 1 wherein the thermal manager comprises arelationship between the cooling fan speed and an airflow rate throughthe enclosure.
 8. The information handling system of claim 1 wherein theenclosure comprises a chassis having plural slots, each slot operable toaccept a processing module, the thermal manager applying powerdissipated by the power supply for each processing module to maintain apredetermined thermal state for each processing module.
 9. Theinformation handling system of claim 8 wherein the information handlingsystem comprises a blade server and the processing modules compriseblade modules.
 10. A method for managing a thermal state in aninformation handling system enclosure, the method comprising: poweringcomponents in the enclosure to process information; flowing air with afan from an inlet over the components to an outlet; sensing thetemperature of the air at the inlet; sensing power dissipated by thepowering components in the enclosure; applying the inlet temperature andthe power dissipated to determine a speed for the fan that maintains apredetermined thermal state at a predetermined position within theenclosure; determining that available fan speeds will not maintain thepredetermined thermal state; and in response to determining, selectingone or more components of the components to power down to allowavailable fan speeds to maintain the predetermined thermal state, theselected component having a predetermined thermal profile.
 11. Themethod of claim 10 further comprising determining that a highestavailable fan speed is inadequate to maintain the predetermined thermalstate; and in response to determining, reducing power consumption of oneor more of the components to maintain the predetermined thermal state.12. The method of claim 11 wherein the applying the inlet temperatureand power dissipated to determine a speed for the fan further comprisesdetermining an airflow rate for the enclosure and fan that absorbsthermal energy produced by the components, wherein the thermal energyproduced by the components relates in a predetermined manner with thepower dissipation.
 13. The method of claim 10 further comprising:sensing the temperature of the air at the outlet; and comparing thetemperature of the air at the outlet with an expected temperature of thepredetermined thermal state.
 14. The method of claim 10 furthercomprising: sensing the temperature of at least one component;determining that a highest available fan speed is inadequate to maintainthe predetermined thermal state; and in response to determining,reducing power consumed by the at least one component.
 15. The method ofclaim 14 wherein the at least one component comprises a processor. 16.The method of claim 15 wherein reducing power consumed by the processorfurther comprises reducing power consumed to reduce the temperaturesensed at the processor to a predetermined temperature.
 17. A system formanaging a thermal state in an information handling system enclosure,the system comprising: a fan operable to provide a cooling airflow atplural selectable speeds; a temperature sensor operable to sense airtemperature at an inlet of the information handling system enclosure; apower manager operable to determine power provided to run electroniccomponents disposed within the information handling system enclosure,the electronic components operable to cooperate to process information;and a thermal manager interfaced with the fan, the temperature sensorand the power manager, the thermal manager operable to apply the sensedinlet air temperature and the determined power for a set of less thanall of the components to select a fan speed to manage the thermal statein the information handling system enclosure associated with the set ofless than all of the components within predetermined constraints;wherein the thermal manager is further operable to determine that noneof the plural selectable fan speeds will maintain the predeterminedconstraints and, in response, to select one or more components of thecomponents to power down to allow a selected of the plural selectablefan speeds to maintain the predetermined constraints, the selectedcomponent having a predetermined thermal profile.
 18. The system ofclaim 17 wherein the thermal manager is further operable to power downone or more of the components to manage the thermal state in theinformation handling system enclosure.
 19. The system of claim 17wherein the power manager is further operable to determine powerprovided to run components in each of plural modules and the thermalmanager is further operable to apply the determined power in each of theplural modules to manage the thermal state in each of the pluralmodules.